Re: General mail/dial-up question
On Wed, May 12, 1999 at 09:38:18AM -0500, Wade wrote: > My very fuzzy understanding of how this works: Windoze connects to the > dial-up server and uses the dial-up server's port 25 to connect to the qmail > server's port 25 to send/receive mail. Is that it, or am I missing the big > picture - again? Too bad. Try again. The users connect thru the dial-up server (which is completely transparent to them) to port 25 on the qmail server to _send_ mail. They get their incoming mail thru POP3 (port 110 on the qmail server). > The point of this (other than the joy of figuring out how it works :) is > that they now want to limit some users to sending and receiving e-mail only. > If I understand correctly, I just need to find a way to limit those users to > accessing only port 25 of the dial-up server. ? And port 110, if you want them to get their mail too :) Greetz, Peter -- | 'He broke my heart,| Peter van Dijk | I broke his neck' | [EMAIL PROTECTED] | nognikz - As the sun |Hardbeat@ircnet - #cistron/#linux.nl | | Hardbeat@undernet - #groningen/#kinkfm/#vdh |
RE: General mail/dial-up question
Duh... That's what I started out thinking, and I let someone convince me that 25 was bi-directional and handled both on a LAN. Excuse me while I go Snipe hunting. :) > -Original Message- > From: Peter van Dijk [mailto:[EMAIL PROTECTED]] > The users connect thru the dial-up server (which is > completely transparent > to them) to port 25 on the qmail server to _send_ mail. They get their > incoming mail thru POP3 (port 110 on the qmail server). So do the connections actually go through ports 25 and 110 on the dial-up server to connect to ports 25 and 110 on the mail server? I assume the dial-up server sees a request to send/receive mail using a certain server and then makes the appropriate connections. But since it's transparent to the requesting program, does it still have to use the same ports? For some reason I've always had trouble understanding the "port" concept. Almost as bad a trying to figure out which direction electricity flows in! :) -wade
Re: General mail/dial-up question
On Wed, May 12, 1999 at 10:20:58AM -0500, Wade wrote: > Duh... That's what I started out thinking, and I let someone convince me > that 25 was bi-directional and handled both on a LAN. Excuse me while I go > Snipe hunting. :) > > > -Original Message- > > From: Peter van Dijk [mailto:[EMAIL PROTECTED]] > > > The users connect thru the dial-up server (which is > > completely transparent > > to them) to port 25 on the qmail server to _send_ mail. They get their > > incoming mail thru POP3 (port 110 on the qmail server). > > So do the connections actually go through ports 25 and 110 on the dial-up > server to connect to ports 25 and 110 on the mail server? I assume the > dial-up server sees a request to send/receive mail using a certain server > and then makes the appropriate connections. But since it's transparent to > the requesting program, does it still have to use the same ports? For some > reason I've always had trouble understanding the "port" concept. Almost as > bad a trying to figure out which direction electricity flows in! :) The dialup-server is just a dumb machine that looks at the destination IP in the packets your SMTP connection is made of. It forwards these packets to the correct IP. _that_ IP then starts looking at the port to see what to do with it. Ofcourse, if you configure your dial-up machine to allow people only access to port 25 on the mailserver, the dial-up machine will _look_ at the port [and throw the packet away if it's not 25 or 110], but it will not actually _do_ anything with the port. That's still just passed on straight to the mailserver. Greetz, Peter -- | 'He broke my heart,| Peter van Dijk | I broke his neck' | [EMAIL PROTECTED] | nognikz - As the sun |Hardbeat@ircnet - #cistron/#linux.nl | | Hardbeat@undernet - #groningen/#kinkfm/#vdh |
